Preheat your oven to 375°F (190°C) and butter a 12-inch cast iron skillet or medium casserole dish.

In a large mixing bowl, whisk together the pumpkin puree, granulated sugar, large eggs, pumpkin pie spice, salt, and vanilla extract until smooth. Slowly add the heavy cream, mixing until creamy.

Pour the pumpkin filling into the prepared skillet and smooth the surface.

In a separate bowl, mix the all-purpose flour, sugar, cinnamon, and a pinch of salt. Pour in the melted unsalted butter and mix until it resembles coarse crumbs.

Sprinkle the streusel mixture over the pumpkin layer.

Bake in the preheated oven for 40-45 minutes until the filling is set and the streusel is golden brown.

Let cool for about 10 minutes before serving.